Conventionally, there has been known a substrate mounting table including an electrostatic chuck having therein an electrode for electrostatic adsorption and a base for adjusting the temperature of the electrostatic chuck (see, e.g., Japanese Patent Application Publication No. 2005-33181). In the substrate mounting table disclosed in the above-cited reference, the electrostatic chuck and the base are adhesively integrated with each other through an adhesive layer. The upper surface of the base has a substantially mesa shape, and the electrostatic chuck is disposed on the upper surface (mounting surface) of the mesa plateau. The upper surface of the electrostatic chuck has a larger surface area than the mounting surface. As a result, the electrostatic chuck is disposed in a state where its edge protrudes radially outwardly beyond the mounting surface. Around the side surface of the adhesive layer, a flexible coating member with a resistance to plasma is provided. The coating member is tightly attached on the side surface of the electrostatic chuck, an end portion of the lower surface of the electrostatic chuck, and the upper surface (periphery) of the base other than the mesa plateau. As another example, the coating member is tightly attached on the side surface of the electrostatic chuck, the end portion of the lower surface of the electrostatic chuck, the upper surface of the base other than the mesa plateau, and the side surface of the mesa plateau of the base. Accordingly, the deterioration of the adhesive layer may be prevented because the side peripheral surface of the adhesive layer is protected by the coating member from active species and the like generated by a plasma.
However, when heat is applied to the substrate mounting table disclosed in the above-cited reference, the coating member may be subjected to a significant thermal expansion/contraction depending on the material of the coating member. In the case when the coating member is largely thermally expanded, the adhesive layer may be peeled off due to a force pushing up the end portion of the lower surface of the electrostatic chuck. Further, when the coating member is largely thermally contracted, a gap may be formed between the coating member and the end portion of the lower surface of the electrostatic chuck and the plasma or the like may enter the gap. Therefore, in the art, there have been required a substrate mounting table and a substrate processing apparatus capable of adequately protect the adhesive layer bonding the base and the electrostatic chuck together.